Plaster of paris supported on fabric or gauze has been used almost exclusively in the preparation of surgical casts designed to immobilize and support portions of the body, e.g. a leg arm, wrist, neck and the like. Plaster of paris is inexpensive, convenient and ready to use after simply dipping in water. Moreover, practically all physicians, particularly orthopedic specialists, have long worked with the plaster of paris medium and are very familiar with the application. Once having mastered the art of working with plaster of paris they are reluctant to learn the different techniques associated with other media.
Nonetheless plaster of paris has certain shortcomings. It is relatively heavy and can be damaged by wetting with water. It is also substantially opaque to x-rays, thus sometimes requiring that a cast be removed to ascertain, for example, whether a fracture has healed satisfactorily.
The various aforementioned problems with plaster of Paris orthopedic bandages have led to the development of orthopedic bandages such as the bandage described in U.S. Pat. No. 3,630,194. This bandage utilizes as a cast forming composition a mixture including a water soluble monomer selected from the group consisting of DAA, N-IPA and mixtures thereof, said monomers being polymerizable, in the presence of water, by means of a redox catalyst system which comprises an oxidation component and a reducing agent. This bandage is hardened in a manner similar to the prior art plaster of paris bandages by dipping the bandage into tap water. The advantage of this method of initiation is that, unlike certain other bandages which use thermoplastic sheets or apply hardenable resins from a paste, the technician working with the bandage does not have to learn new techniques for preparing a cast.
Although satisfactory in many ways, it has been found that the orthopedic bandages described in U.S. Pat. No. 3,630,194 suffered from certain drawbacks. For example, the bandages, after dipping in water to initiate the hardening thereof, are stiff, non-conformable to the limb and difficult to wrap. As further discussed below, it has been found that the addition of a 1,2-ditertiary glycol to the cast forming composition alleviates the above drawbacks. Furthermore, pinacol, the preferred 1,2-ditertiary glycol from the standpoint of improved conformability, also unexpectedly increases the working time of the instant orthopedic bandage.